196 WALKER-ARNOTT, ON ARACHNOIDISCUS, ETC. 
Prevrosicma.—I find from some correspondents that the 
remarks I made in the last number of the ‘ Microsc. Journ.,’ 
p- 164, have conveyed more than one erroneous impression. 
I had no intention to find fault with any gentlemen supply- 
ing Dr. Donkin with the information they gave; they got 
the information from friends in a perfectly legitimate way, 
and furnished it as legitimately, although from not coming 
directly from myself, it was partly meorrect and partly mis- 
understood. Had Dr. D. applied to me, I would have at 
once explained to him how the diatom in question came to 
be referred to Amphiprora; and then, I have no doubt, the 
paragraph at p. 33, which appeared to me uncourteous, would 
not have been written. Mere MS. trivial names are, by 
common consent, referred to every day; but unless the 
giver has himself published his reasons for such names, 
whether generic or specific, they are quoted without note 
or comment, and solely as provisional ones or synonyms ; 
a departure from this would imply a right to give to the 
public information not imtended for it, and which was ob- 
tained privately. This right, however, happily does not 
exist ;* for if it did, it would destroy all friendly intercourse 
by letters. 
The synonyms I gave were less with the intention to criti- 
cise Dr. Donkin’s new forms, as to show that others had 
been engaged also on several of the same; and that in the 
present dislocated state of this branch of science, (now that 
we have lost Professor Smith as a common bond of connec- 
tion,) it is desirable that before any one publishes new or 
supposed new British species, he should make extensive 
inquiries among diatom collectors, so as to discover if the 
same have not previously occurred to them, but perhaps under 
a slightly different form, and if the difference cannot be 
explained by extrinsic causes. By submitting the diagnosis, 
and taking the opinions of several, naturalists as well as 
microscopists, students of cause as well as those of effect, a 
person is more likely to come to a correct conclusion than 
by trusting to oneself, or consulting those only who are likely 
to agree with him; at all events, the species is thus amply 
discussed before publication, and not left to after-criticism. 
Some of the synonyms I adduced (at p. 165) are not pub- 
lished, and although the species have been long known and 
in many of our cabinets, and although probably Dr. Donkin 
would have adopted such MS. names, so far as they were 
* See, in regard to private correspondence, ‘Notes and Queries,’ 2d 
series, vol. v, pp. 47, 76. 
